As fuel cell power plants are being integrated into useable vehicles, developing efficient ways of supplying the fuel needed to operate the fuel cell stack becomes more critical. Hydrogen gas is the common fuel input to the stack. It may be reformed on-board a vehicle by processing fuels such as gasoline or methanol through a reformer to convert the fuel to reformate comprising hydrogen, carbon dioxide, carbon monoxide, and water vapor. The reformate may be passed through a shift converter and gas purifiers to remove carbon monoxide before delivering the hydrogen to the fuel cell stack. This complete reformation process is not only complex to engineer, but consumes valuable packaging space and mass.
As an alternative to reforming fuels on-board, hydrogen gas may be stored on-board in suitable tanks. While pure hydrogen gas is an efficient fuel, storing it on-board a vehicle has drawbacks related to packaging and mass. Instead of storing hydrogen in its gaseous state, hydrogen may be taken-up and captured by a hydrogen-retention material contained within an on-board storage tank. With either of these storage methods, the storage tank will need to be refilled with hydrogen gas by a typical consumer at a refueling station. This presents challenges for the interface between the refueling station and the vehicle.